2009 Saturn Vue Green Line Two-Mode Hybrid

GM does its two-mode tango with Saturn's cute ute.

Not to be confused with the Vue Green Line "mild hybrid" already on dealers' lots, the latest Vue Green Line employs a "full hybrid" system utilizing GM's new two-mode technology. GM will sell the two Vues side by side and, to further confuse consumers, will add a third hybrid later—a plug-in version of the two-mode Vue.

Co-developed with BMW and the former DaimlerChrysler, the current two-mode system promises nearly transparent operation while significantly boosting efficiency. While this technology made its GM debut in the 2008 Chevy Tahoe and GMC Yukon full-size hybrid SUVs, Chrysler's first use of the system is on the 2009 Dodge Durango and Chrysler Aspen. BMW will subsequently debut the two-mode system on the upcoming 2010 BMW X6 ActiveHybrid.

Instead of the V-8 used by larger big hybrid SUVs, the newest Saturn Vue Green Line combines GM's 3.6-liter DOHC direct-injection V-6 engine (first introduced in the 2008 Cadillac CTS) with two 55-kilowatt electric motors. To keep the motors spinning, the system employs 22 batteries stowed underneath the cargo floor. This also marks the first use of the two-mode technology in a front-drive vehicle.

As the name "two mode" implies, the system can operate in two modes, with the powertrain making the choice based on vehicle speed and load. GM's new 2MT70 automatic transmission contains not only four fixed-ratio gears but also two sets of continuously variable ratios, and it can swap between them to maximize efficiency in various driving situations, as in the Tahoe/Yukon.

The first mode, which is active below 40 mph, allows the vehicle to run on either electric or gasoline power, or both, with one electric motor acting as a generator and the other providing propulsion. And whereas most hybrids lose their efficacy at high speeds or while towing, this is when the second mode kicks in, as the stepped-gearing capability delivers all engine power directly to the driving wheels. This avoids power loss through the less-efficient electrical path that other hybrids use, thus saves fuel even in highway driving. Competitive hybrid systems, such as Toyota's, operate in a single mode with a gasoline engine mated to a continuously variable transmission, with minimal fuel saving at high speeds.

Additional fuel-economy improvements are achieved by cutting off the engine at idle and during deceleration (similar to a mild hybrid's operation) through the use of regenerative braking and by allowing the vehicle to operate on electricity alone at low speeds or in reverse. An all-wheel-drive system will not be offered with the two-mode Vue Green Line.

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*AccuPayment estimates payments under various scenarios for budgeting and informational purposes only. AccuPayment does not state credit or lease terms that are available from a creditor or lessor, and AccuPayment is not an offer or promotion of a credit or lease transaction.